# US 8,786,784 B2 · Pseudo digital gain control for broadband tuner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,784 B2 - Document ID: US8786784B2 - Status: Granted - Kind: B2 - Application number: 13/460,508 - Filed: 2012-04-30 - Published: 2012-08-23 - Granted: 2014-07-22 - Earliest claimed: 2006-11-07 - Assignees: CSR Technology Inc. - Applicants: Timothy M. Magnusen - Inventors: Timothy M. Magnusen - Web page: https://patentgrep.com/patent/US8786784B2 ## CPC - H03G 1/0088: {using discontinuously variable devices, e.g. switch-operated} - H03G 3/001: {Digital control of analog signals} - H03G: CONTROL OF AMPLIFICATION ## Abstract A digital level control circuit, such as an Automatic Gain Control, includes a plurality of digitally selectable signal levels with transitions between levels gradually varied to avoid signal output level discontinuities. An up/down counter may be used to incrementally stepwise transition an output signal between the digitally selectable output levels. Stepwise application of a control signal to the appropriate switching elements (e.g., FETs) forming an attenuator circuit may be implemented to moderate a switching time of the switching elements to provide a more gradual transition between element operating states. A deglitch circuit may be employed to latch the switching elements to achieve the desired state at the end of a desired switching transition period. ## Claims ### Claim 1 A level control circuit comprising: a detector configured to detect a change in level value defined by a digital level control signal; and a moderator configured to monotonically change a level of an input signal over some predefined transition period in response to said digital level control signal so as to achieve a desired output signal level by: determining a desired configuration of switching element states to effectuate said desired signal level, and selectively supplying a sequence of monotonically changing control voltages to ones of said switching elements to transition between an initial configuration and said desired configuration; and a deglitch circuit connected to said moderator and to said switching elements, said deglitch circuit configured to coordinate control signals between said moderator and said switching elements such that a minimum number of transitions are permitted to occur at one time. ### Claim 2 (depends on 1) The circuit according to claim 1 wherein said moderator is further configured to incrementally change a conduction state of a switching element during a transition between fully on and off states of said switching element. ### Claim 3 (depends on 1) The circuit according to claim 1 wherein said moderator comprises: a counter configured to provide a changing digital count value; a digital-to-analog converter configured to convert said digital count value into an analog signal level; and an output circuit configured to supply said analog signal level to a switching element during said transition period. ### Claim 4 (depends on 3) The circuit according to claim 3 further comprising: a latch configured to output a level of said analog signal supplied to said switching element upon termination of said transition period. ### Claim 5 (depends on 1) The circuit according to claim 1 further comprising: a deglitch circuit configured to monitor a level of an analog signal and, in response, provide said digital level control signal for maintaining a level of said analog signal at a desired value. ### Claim 6 (depends on 1) The circuit according to claim 1 wherein said moderator is further configured to supply a incrementally changing control voltage to vary a conduction level of a switching element over a transition period. ### Claim 7 A method of operating a level control circuit comprising the steps of: detecting a change in level value defined by a digital level control signal; monotonically changing a level of an input signal over some predefined transition period in response to said digital signal so as to achieve a desired output signal level; determining a desired configuration of switching element states to effectuate said desired signal level, and selectively supplying a sequence of monotonically changing control voltages to ones of said switching elements to transition between an initial configuration and said desired configuration; and coordinating, using a deglitch circuit connected to said moderator and to said switching elements, control signals between said moderator and said switching elements such that a minimum number of transitions are permitted to occur at one time. ### Claim 8 (depends on 7) The method according to claim 7 wherein said step of monotonically changing said level of said input signal includes incrementally changing a conduction state of a switching element during a transition between fully on and off states of said switching element. ### Claim 9 (depends on 7) The method according to claim 7 wherein said step of monotonically changing said level of said input signal includes steps of: counting to provide a changing digital count value; converting said digital count value into an analog signal level; and supplying said analog signal level to a switching element during said transition period. ### Claim 10 (depends on 9) The method according to claim 9 further comprising the step of latching an output level of said analog signal supplied to said switching element upon termination of said transition period. ### Claim 11 (depends on 7) The method according to claim 7 further comprising a step of: monitoring a level of an analog signal and, in response, providing said digital level control signal for maintaining a level of said analog signal at a desired value. ### Claim 12 (depends on 7) The method according to claim 7 wherein said step of monotonically changing a level of said input signal includes a step of supplying a incrementally changing a control voltage to vary a conduction level of a switching element over a transition period.